Program-Controlled Washing Machine

ABSTRACT

To optimize the completeness, uniformity and reproducibility of a wetting process in a program-controlled washing machine, which can be adjusted according to the amount of laundry in a washing drum, which is rotationally mounted in a lye container about a non-vertical axis by means of a water supply system and by means a control device, said process being temporally controlled by the supply of water into the lye container. According to the invention, the wetting process is divided up into a series of phases corresponding to the various amounts (small, medium, large) of laundry that is to be treated. As a result, it is possible to adapt the wetting process according to the number and formation of individual phases in relation to the amount of laundry that is to be treated.

The invention relates to a program-controlled washing machine with a wetting process which can be adapted to the amount of laundry in a laundry drum, which is mounted in a tub such that it can rotate about a non-vertical axis, by means of a water supply system and a control device which can temporally control the supply of water into the tub, as well as a method for adapting the wetting process of a laundry batch to be treated in a laundry drum of a washing machine.

When adapting the quantities of water required for washing in program-controlled washing machines, the wetting processes in particular should be optimised in such a manner that for each amount of laundry and the quantity of water in the tub which is adapted thereto, the respective laundry batch is wetted completely and uniformly in the shortest possible time, before the actual washing process begins.

Wetting phases known so far use an adapted reversing rhythm of the laundry drum at reduced drum speed or pre-filling of the tub when the laundry drum is at a standstill, followed by continuous turning of the laundry drum in the scoop direction and a following wetting phase as described hereinbefore, or with an inserted spinning phase to accelerate the penetration of the washing solution into the laundry as described hereinbefore.

Other wetting phases provide different sequences with standstill times of the laundry drum, unidirectional or reversing drum movement at low speed and possibly reduced reversing rhythms.

The wetting processes used so far have not been satisfactory with regard to an optimised use of process sequences. In particular, the known wetting processes have hardly taken adequate account of differently sized laundry batches so that no complete wetting takes place in the case of very large laundry batches (close to the load limit) whereas small laundry batches are treated for too long in the wetting phase, measured by their wetting success. In addition, in the known wetting processes the uniformity of the wetting leaves something to be desired.

It is thus the object of the invention to set up wetting sequences in such a manner that the uniformity of the wetting can be satisfactory in each laundry batch and at the same time, the wetting processes can be automatically adapted to the quantity of laundry of a laundry batch in that the laundry is wetted with the optimum quantity of water or washing solution with uniform wetting so that the washing process can thus be begun.

According to the invention, a washing machine described initially is constructed by dividing the wetting process into as many wetting phases as the number of quantity stages provided for the laundry to be treated.

This division of the wetting process allows the respective steps of the process to be adapted to the amount of laundry present.

In an embodiment of the invention, each phase of the wetting process comprises a section during which a predetermined level of water supplied during this section is set in the tub whilst the laundry drum turns continuously in a specific direction. It is thereby possible for the first time to reliably estimate the amount of laundry to be treated in each phase of the wetting process in order to adapt the subsequent profile of the wetting process thereto.

It is advantageous according to a further development of the invention if the direction of rotation of the laundry drum corresponds to the direction of effectiveness of a scoop device. Then, specifically during this section in which the level of the supplied water is determined continuously, the laundry is already intensively impregnated so that the quantity supplied can be determined sufficiently accurately. A measuring device can be provided to determine that the predetermined level has been reached; for this purpose, a time-measuring device can be used as a measuring device to determine the opening time of an intake valve or a liquid-quantity measuring device can be used to determine the amount of liquid supplied.

The section advantageously lasts until the predetermined level is reached. According to a further embodiment of the invention, after a comparison with a reference value it can be decided whether, as a result of the size of the laundry batch, the section should be followed by a second and/or further phase of the wetting process to which a stage with reversing drum movement is allocated. This stage can be incorporated, for example in the section with continuous turning of the drum or ahead of this section.

If, according to a further advantageous embodiment of the invention, the measuring device for achieving the predetermined level and/or the comparator is switched off during the reversing drum movement, an appropriate wetting of the laundry batch can be carried out without supplying further water which would cause the dampening in the present laundry batch, which is perhaps too small for so much water in a manner unrecognised hitherto, to reach oversaturation.

The size of the laundry batch can only be determined in the following section of the wetting by unidirectional turning of the laundry drum in the scoop direction again using the amount of water supplied which is now to be measured. For this purpose a rotational speed of about 20 rpm has proved to be very suitable in a given geometry of the tub/drum system.

Accordingly, the reversing drum movement in coordination with the design features of the tub and/or the laundry drum at a rotational speed in the range of 40 rpm has proved to be very suitable. From these conditions, the phases of the wetting process can last between 10 and 40 seconds which overall results in a temporally ideally optimised wetting process.

The embodiment of the washing machine according to the invention as well as suitable process steps for this embodiment are explained in detail hereinafter with reference to an exemplary embodiment for a wetting process. In the figures:

FIG. 1 is a wetting process for a large laundry batch using a diagram and

FIG. 2 is a schematic diagram of the relevant parts of a washing machine for the invention, in which a wetting process is applied according to FIG. 1.

A prerequisite for the description of the wetting process shown in FIG. 1 is a washing machine according to FIG. 2 comprising a tub 1 in which a laundry drum 2 is mounted and which is driven by a drive motor. According to more recent findings for the ergonometry when dealing with such washing machines, the axis of rotation 3 of the laundry drum 2 is upwardly directed from the horizontal towards the front by a small angle (e.g. 13°) so that the user of the washing machine obtains easier access and view into the interior of the laundry drum 2. As a result of this arrangement in cooperation with specially shaped laundry entraining devices 4 and scoop devices 5 for the washing liquid 6 on the inner surface of the drum jacket, more intensive flooding of the laundry 7 with washing liquid and a reduction in the so-called free liquid is also achieved, this free liquid designating the amount of washing liquid in the tub 1 which can no longer be absorbed by the saturated laundry (substantially below the lowest point of the laundry drum 2).

The washing machine also has a liquid supply system comprising a water connection fitting for the domestic water network 8, an electrically controllable valve 9 and an inlet 10 to the tub 1 which can optionally be guided via a detergent flushing device 11 from which the water supply can convey portions of detergent into the tub. The valve 9 can be controlled by a control device 12 depending on a program sequence plan which can be bound to a time program and/or to reaching specific measured values of parameters (washing liquid level, temperature of washing liquid, rotational speed of the laundry drum etc.) inside the washing machine. Also located in the tub 1 is a liquid heating device 13 which can likewise be switched by the control device 12 and according to similar criteria.

A washing program typically begins, as in FIG. 1, with the opening of the valve to pass water from the domestic water network 8 into the tub 1. There, the water should be brought into contact as quickly as possible with the laundry 7 stored in the laundry drum 2 so that on the one hand the entrained detergent and on the other hand, the heat introduced by the heating device 13 can be transferred to the laundry 7 as rapidly as possible.

In the diagram in FIG. 1 the rotational speed n of the laundry drum 2 is plotted as a function of time t because the rotational speed control in particular characterises the new type of wetting process. The water supply, optionally supply of detergent and control of the heating device 13 are carried out in accordance with the prior art. The overall wetting process stored in the program comprises three phases Ph1 to Ph3 which are faded in or out as required. The wetting process is followed directly by the washing process W which continues with a known form of reversing drum movement.

In phase Ph1, after a sufficient quantity of liquid has been supplied, the drum 2 is set in motion. In this case, it is moved exclusively in one direction and specifically in the direction (arrow 14) in which the scoop devices 5 on the laundry drum 2 act as prescribed. The desired rotational speed of the laundry drum 2 is set at a value of about 20 rpm for the selected geometrical dimensions of the laundry drum which, however, are not described in further detail here. The actual rotational speed however fluctuates about this value according to the respective distribution of the laundry batch in the laundry drum. The drum movement is maintained for a duration of about 15 seconds. Specifically, the movement lasts until the required initial quantity of supplied water is present in the tub 1.

The value of this initial quantity is determined and specifically either by measuring the valve opening time which is a measure for the absolute quantity supplied assuming that the specific quantity supplied by the valve 9 is sufficiently uniform, or by direct measurement of the quantity supplied, for example, using a flow meter (not shown). The value for the initial quantity is set in relation to the attainment of the desired liquid level N_(1-o) in the tub (at 121) which is monitored by a level measuring device 15 so that the amount which has been absorbed by the laundry batch 7 is obtained directly from this. A large batch of laundry absorbs a large amount of water so that the initial quantity of water supplied before reaching the desired level N_(1-o) in the tub 1 increases more rapidly than for smaller laundry batches.

The invention makes use of the differences described between different-sided laundry batches in order to decide, using these differences, whether the wetting process can be interrupted here (in the case of a small laundry batch) or whether it must be continued in a particular manner. In the case of a small laundry batch, the initial quantity of water supplied is almost completely (apart from the remainder of the free liquid) absorbed because all the parts of the laundry batch come into contact with the supplied water without appreciable delay. If the laundry batch has been identified as small in this way, then at this point a transition takes place immediately to the washing phase W.

If it has been established in the manner described previously as assumed that the laundry batch to be treated is so large that the liquid level reached in this phase Ph1 cannot be sufficient to completely wet the laundry, a second phase Ph2 of the wetting process is initiated. This second phase begins with a first section A_(R2) and a reversing drum movement with, for example, four short intervals of rotational speeds of up to 40 rpm in each direction. Single short-spin intervals can also be embedded in this section to flood the laundry better with the newly absorbed liquid.

In any case, the level regulation is switched off in this section A_(R2), i.e. the water supply is not switched on when the actual liquid level falls below the desired level. Thorough mixing of the laundry batch is hereby achieved and the laundry is also given the opportunity to become further wetted by the water which has already been supplied. This section A_(R2) can be several minutes long and can contain more intervals than is represented here by merely a few intervals within a relatively short time duration. The duration of this section A_(R2) is substantially dependent on the selected reversing rhythm, the liquid level and the technically complex circumstances.

However, this is followed by a section in which the laundry drum 2 is driven unidirectionally, as in the phase Ph1 in the scoop direction 14 at a rotational speed of about 20 rpm. This section A_(D2) is again used to check the absorbency of the laundry batch 7, and therefore indirectly the amount of laundry. For this purpose (at 15) it is measured whether the liquid level falls below a limiting value N_(2-u) which is considered to be a measure for the amount of laundry assigned to this phase. If the value falls below this limit, water is again supplied during the sustained movement of the laundry drum 2 until the level switching value N_(2-o) is reached. The total quantity of water supplied before reaching the switching point N_(2-o), as in the phase Ph1, is a measure for the amount of water and determines whether (in the case of a medium amount of laundry) a transition is now made directly to the washing process or whether a further phase Ph3 of the wetting process is initiated. For example, the typical value of the total amount of water for specifying “medium amount of laundry” is a maximum of 18 litres.

However, if a large laundry batch is present (total amount of water over 18 litres), a further phase Ph3 is initiated which again begins with a first section A_(R3) and reversing drum movements with short intervals of rotational speeds up to 40 rpm in each direction and possibly even with inserted short-spin intervals. The level regulation is again switched off here so that no further water is introduced during the wetting movement. The structure of the movement sequence and its dependences correspond to the same section A_(R2) in the phase Ph2.

This phase Ph3 is also followed by a section A_(D3) in which the drum 2 is continuously driven unidirectionally at about 20 rpm and which is again used for filling with water. The desired liquid level N_(3-o) however is now the level provided for washing and is no longer used to determine the amount of laundry. After a certain duration of thorough mixing in the scoop direction, the washing process begins with known parameters. The duration of the thorough mixing in this continuous rotation section can be varied from one phase to another; this duration preferably becomes longer with increasing number of phases.

The levels of the individual phases should also increase, but at least from the first phase Ph1 to the second phase Ph2. Liquid levels increasing with the number of the phase increase the relative total amount of water for large laundry batches; however, more intensive dampening of the laundry is achieved more rapidly. If a constant level is selected in higher phases, a high scoop performance of the laundry entraining devices 4 and good regrouping of the laundry within the laundry batch should be ensured for satisfactory dampening.

The laundry batches can also be differentiated more strongly as is convenient. However, this involves an increase in the number of phase which then can be shortened in each case, particularly in the reversing section A_(Rx). Nevertheless, the entire program duration of a wash cycle can be shortened as a result of the more uniform dampening.

A level- or load-dependent matching of the drum speed in the scoop direction 14 can be appropriate to optimise the scoop action if the dampening is to be intensified and/or accelerated. Instead of the connection ahead thereof which is proposed, it can be advantageous for programming reasons to incorporate the reversing phases in the continuous rotation phases.

The reproducibility of the dampening and the washing action can advantageously be improved with the measures according to the invention because the water is let in at defined times and under defined conditions. In an oblique drum system, as explained initially, the adaptation of the water level to the amounts of laundry introduced can result in refinement of the load-dependent process conditions, especially in the case of small laundry batches. In addition, the uniform dampening is improved in the case of large laundry batches. This is aimed overall at optimising the required amounts of water so that as a result of the differentiation considered over longer time intervals, a saving on the water consumption can be observed. 

1-17. (canceled)
 18. A program-controlled washing machine comprising: a tub and a laundry drum mounted within the tub and receiving laundry, the drum being mounted for rotation with respect to the tub about a non-vertical axis; a water supply system supplying water into the tub in a wetting process; and a control device controlling the water supply system and wetting process and adjusting the wetting process in response to the amount of laundry in the laundry drum, the wetting process being divided into as many phases as a number of quantity stages provided for the laundry to be treated.
 19. The washing machine according to claim 18, wherein each phase of the wetting process comprises a section during which a predetermined level of water supplied during this section is set in the tub while the laundry drum turns continuously in a specific direction.
 20. The washing machine according to claim 18, wherein the laundry drum includes a scoop device and the direction of rotation of the laundry drum corresponds to the direction of effectiveness of the scoop device.
 21. The washing machine according to claim 19, wherein the section lasts until the predetermined level is reached.
 22. The washing machine according to claim 21, wherein a measuring device is provided to determine that the predetermined level is reached.
 23. The washing machine according to claim 22, wherein the water supply system includes an intake valve and a time-measuring device is used as an additional measuring device to determine an opening time of the intake valve.
 24. The washing machine according to claim 22, further comprising a liquid-quantity measuring device providing an additional measuring device to determine the amount of liquid supplied.
 25. The washing machine according to claim 20, wherein the control device has a comparator for the measurement parameter for ending the section.
 26. The washing machine according to claim 18, wherein in at least one of the second and a further phase of the wetting process, a stage with reversing drum movement is allocated to the section.
 27. The washing machine according to claim 26, wherein the stage with reversing drum movement is incorporated ahead of the section.
 28. The washing machine according to claim 27, wherein the measuring device for achieving at least one of the predetermined level and the comparator is switched off during the reversing drum movement.
 29. The washing machine according to claim 19, wherein the level in at least one of the second and further phase is predetermined depending on the washing quantity stage.
 30. The washing machine according to claim 19, wherein movement of the drum in the specific direction is carried out in coordination with the design features of the tub and the laundry drum at a rotational speed of about 20 rpm.
 31. The washing machine according to claim 27, wherein the reversing drum movement is carried out in coordination with the design features of the tub and the laundry drum at a rotational speed of about 40 rpm.
 32. The washing machine according to claim 18, wherein the phases last between 10 and 40 seconds.
 33. A method for operating a program-controlled washing machine comprising a tub and a laundry drum mounted within the tub and receiving laundry, the drum being mounted for rotation with respect to the tub about a non-vertical axis, a water supply system supplying water into the tub in a wetting process, and a control device controlling the water supply system and the wetting process, the method comprising the acts of: coordinating a wetting process of a laundry batch to be treated in a laundry drum of a washing machine; performing a first phase of the wetting process and supplying a predetermined quantity of water with the water supply system with unidirectional drum movement; and performing a second phase of the wetting process if a small amount of washing solution according to a small amount of laundry has been determined in the first phase according to measurement parameters.
 34. The method according to claim 33, wherein in the second phase includes a section with unidirectional drum movement, the method further comprising the acts of: determining the laundry quantity stage by setting the amount of water supplied in relation to an allocated laundry quantity stage; and initiating a further phase for the wetting process if the washing solution level allocated to the current phase for the amount of laundry is exceeded. 